Quote:
Originally Posted by strupgolf
On 1989 944S2 cars, are they R12 or R134? How can you tell if your car has been converted to 134 if it has? And, is recharging a DIY job? Thanks.
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I think cars didn't change over to 134 until 92 or 93. There should be a sticker that gives the information on refrigerant capacity. If it was converted correctly, there should be some quick connect fitting adapters installed on the schraeder valves to allow you to connect the 134 charging hose directly. Otherwise, who knows. Easiest way would be to get your hands on some R12, but most people won't sell it to you without a EPA certification (which actually is not hard to get). R12 is getting harder to find and it won't sell cheap.
I can't remember off the top of my head the oil compatibility issues of what doesn't work with what when converting, but generally, it requires recovering any existing refrigerant (you know...
), draining as much existing oil as possible, flushing out the system (depending on how clean it is already, what oil you're going to use, and how anal you are...it is complicated as there is a TXV in the system and you would have to remove it prior to flushing), replacing o-rings on any disassembled connections, leak testing with nitrogen (kind of optional as most people don't have the equipment, but is a timesaver if something leaks), fixing any leaks found, adding new oil that will not break down in the presence of CFC and mineral oil residue (want to say it's PAG oil, but I don't remember...you cannot use mineral oil, as it is not miscible with HFC refrigerants and will not return to the compressor properly), replacing the receiver drier, evacuate the system, charge to about 8-12 deg F of subcooling on a hot day. If you don't leak test with nitrogen, use a UV sensitive oil to help find leaks after the fact. Checking if the system holds vacuum will tell you that it is dry and that there are no major leaks, but it will not ensure it is completely leak free. Leak testing with vacuum is the same as leak testing with 14 psi nitrogen...not very useful.